You'll have to either take a taxi (likely to be pretty expensive) or a long distance van service such as Roadrunner (not sure if they go to Palm Springs) Their number is 1-800-247-7919. Also give Super Shuttle a shot (I have used them before in different cities and have liked their services). You can reach them at 310-782-6600.

well, that's a nice way to put it. anyway, practicality and comfort is never an option with the service but a guarantee in every ride. just book one early to avoid the hassle of any last minute changes of your schedule. til then hope the site provided will help you in your future endeavor regarding the matter.